Power-driven dial feed



IM 2 R. A. SKRIBA ET AL 2,374,464

POWER DRIVEN DIAL FEED Filed April 4, 1941 5 Sheets-Sheet 1 "April 4 R. A. SKRIBA ETAL; 2,374,464

V POWER DRIVEN DIAL FEED "Filed April 4, 1941 '5 Sheets-Sheet 2 QMAggMW April 4 R. A. SKRIBA- ET AL 2,374,464

POWER D RIVEN DIAL FEED Filed April 4, 1941; 5 Sheets-Sheet 3 April 1945. R. A. SKRIBA ET AL 2,374,464

POWER DRIVEN DIAL FEED Filed April 4, 1941 5 Sheets-Sheet Patented .lhpvw 2d, 1945 POWER-DRIVEN DIAL FEED Rudolph A. Skrlba, Chicago, mssna Edgar R.

Miller and Frederick M. Littell, Detroit, Mich, assignors to F. J. Littcll Machine Company,- Chicago, 111., a corporation of Illinois Application April 4, 1941, Serial no; 386,828

7 Claims.

The invention relates to feeds for punch presses and the like and has reference more particularly to a power driven dial feed which may be operated at a speed independently of that of the press and which will control the operations of the press. [in object of the invention is to provide an improved dial feed for presenting articles to apress in succession for riveting and the like and which will incorporate an independent powerimproved driving means for imparting an indexlng notation to the work plate and which indexing rotation may take place at various speeds independently of the driving speed of the press, although the operations of the press are controlled by the indexing rotation so as to occur in timed relation therewith.

A further object of the lnventlonls to provide a series of electrical switches positioned for actuatllon by the indexing mechanism for the work plate and wherein said switches control the riveting or punching operations of the press.

tures of construction and operation as will be more fully described and particularly pointed out 11:1 the specification, drawings and claims appended ereto.

In the drawings which illustrate an embodiment of the device and wherein like reference characters are used to designate like parts- Figure l is a front elevatlonal view of a press equipped with the dial feed of the invention which is partly shown in section;

Flgure 2 is a side elevational view of the press and dial feed of Figure 1 with parts of the dial feed being shown in section to more clearly illustrate their mode of operation;

Figure 3 is a view in top plan of the improved dial feed of the invention with a part of the work p holding plate broken away to illustrate the in- A further object resides in the provision of electrical control switches for the press which will effeel; an operation of the press when all the switches are closed, said switch. means thereby requiring that a number of conditions be fulfilled before the press will produce a punching or rivetlug stroke.

Another object is to provide improved indexing means for the work holding plate including an indexing pawl and holding pawls with electrical control switches associated with certain of said pawls whereby said switches are closed only when said M pawls are in a predetermined position.

Another object resides in the provision of a dial feed for a press having a plurality of work holding stations thereon for retaining the individual work pieces to be assembled and which are successively located under the punch of the press.

Another object of the invention resides in the provision of improved work holding stations for a dial feed having novel means for electing the work following a punching operation thereon.

Another object resides in the provision of a dial feed having improved operation, which will require a minimum number of parts in its constructlon, and which will be relatively economical to manufacture.

With these and various other objects in view, the invention-may consist of certain novel feadexing plate below the same and its association with indexing and holding pawls;

Figure 4 is a fragmentary sectional view taken along a horizontal plane showing the improved structure for imparting rotation to the indexing plate, with the indexing and holding pawls also being illustrated in association with their electrical switches;

Figure 5 is a fragmentary enlarged sectional view taken along line 55 of Figure 4;

Figure 6 is a detail sectional view taken along line 8-6 of Figure 3 showing a work piece about to be riveted by the punch of the press;

Figure 'I is a fragmentary sectional view taken along line I--| of Figure 3 showing the action of the ejector in removing the riveted work pieces from their holder;

Figure 8 is a diagrammaticview showing the solenoid operated mechanism for tripping the press;

Figure 9 is a plan view of the oscillating plate having the slotted arm and indexing pawl for imparting rotation to the indexing plate;

Figure 10 is an elevatlonal view of the driving disc for the oscillating plate;

Figure 11 is a fragmentary plan view with part of the work holding plate being broken away to show the supporting structure therefor; and

Figure 12 is a wiring diagram showing the electrloal connections for the control switches, the solenoid and other electrical elements of the press.

Referring more particularly to Figures 1 and 2 of the drawings, the improved dial feed of the invention isillustrated in associated relation with a conventional punch press 30 having a base 20 including a member 2|, a foot support 22 for the operator, and including an upright substantially rectangular frame portion formed by side mempress, said frame having a bed portion 3| which is suitably fastened by bolts I5, Figure 1, to lugs 16 of the base 20, the same including side walls 23 and 24, front wall 25 and rear wall 26. The frame extends upwardly and the said frame suitably journals at 39 the operating shaft 33 having crank portion 34 located between the standards and also having the fly-wheel 35 rotatably mounted on the extending portion of the shaft projecting beyond the right hand standard, as shown in Figure 1.

A plate 36, supported on the top of the frame 30 to the rear thereof, supports the electric motor 3'! for driving the press, the motor being suitably wired by conductors within conduits 38. The upright frame 30 provides guiding gibs dB for the reciprocating cross head 6| of the press which is operatively connected to the crank portion 33 of the operating shaft by means of a connecting rod 42. The punch 43 of the press, Figure 6, is carried by the part 44 which depends from the reciprocating cross head 3|. The punch is releasably retained within part 53 by means of the set screw 45. It will be understood that the driving motor 31 is connected by any suitable means to the fly-wheel 35 of the press so that upon operation of said motor the fly-wheel. will be continuously rotated at the desired speed. Said flywheel operates continuously although the operating shaft 33 is stationary, except during a riveting operation. The fiy-wheel is suitably journalled on the operating shaft and retained thereon by collar 46 so as to have rotation independently of the shaft. All conventional presses provide a clutch for connecting the fly-wheel with shaft 33 so that a punching operation may take place when the clutch is tripped. The clutch for the press shown in the drawings is diagrammatically indicated by numeral 31, Figure 8.

It will be understood that when said clutch is tripped by means to be presently described that the fly-wheel 35 will be instantl connected to the operating shaft 33 and punch 43 will therefore be reciprocated to effect a riveting operation. The tripping means for clutch Al is constructed and arranged so that one riveting operation takes place for each tripping of the clutch.

The press shown in the drawings is provided with a fly-wheel 35 of relatively small size. It is generally necessary to use a press for performing the riveting operations to be described of fairly large size in order that sufiicient power will be developed to drive the feed table as well as supply the desired power to the punch. The present type of dial feed, which is power driven separate and apart from the press, makes it possible to use a press of much smaller size with standard fly-wheel than would otherwise be the case. The reason for this is that the fly-wheel can be rotated at a much higher speed and accordingly this higher speed will develop the desired momentum and driving power for the punch.

One embodiment of separate and independent drive for the dial feed is shown in Figure 2, wherein it will be observed that the side mem aeraeea ber 23 of the base portion of the press is provided with a bracket 50 suitably secured to the member by screws 5| for supporting an electric motor 52 and variable speed transmission 53.. The motor is connected to the variable speed transmission by coupling 54 and said transmission is provided with a dial 55 and pointer 56 for indicating the particular speed ratio of the transmission and which may be varied by movement of said pointer. The shaft 51, projecting from the variable speed transmission into the 3' gear cover 58, has suitably secured thereto the bevel gear 60 which has meshing engagement with bevel gear 6! fixed to the vertically disposed shaft 62. Shaft 62 is journalled [by member 33, including an integral hub and spider, the latter being secured by screws 64 to the undersurface of the circular capping plate 21. Shaft 62 has the driving disc 65 nonrrotatalbly secured to its upper end so that said disc is driven continuously by motor 52 and at the desired speed as a result of the variable speed transmission 53. A cam 66 is. fixed to the periphery of the driving disc and a crank pin 6'! projects upwardly from the surface thereof, the said crank pin receiving a slider block 68, as shown in Figure 10. The cam will engage the plunger 10, Figures 2 and 5, during each revolution of the disc to cause depression of the same or movement in a direction toward the right. This depression of the plunger against the tension of its backing spring M will effect closing of the switch 12 supported from the undersurface of member 21 in proper position with respect to said plunger.

The function of the driving disc 65 is to impart oscillating movement to the annular plate 13, Figure 9, which plate rests on member 27, being supported by said member for oscillating movement. As shown in Figure 1, member 21 is pp provided with a reinforced central portion providing a hub 14. On the respective sides of the hub the screws 15 securely bolt the bed 3! of the press 30 to the lugs 16, welded to the members 23 and 24 of the base. Additional screws I1, somewhat smaller in size, are provided for fastening the central portion of member 21 to the base of the press. The center stud shaft 18 projects upwardly from hub 14. The stud shaft is suitably bolted to the hub by means of the nut 19 threaded to the lower projecting end thereof and by the enlarged central portion of the stud shaft, which portion securely holds the circular center plate 8| in contact with the upper surface of member 21 and in a central position on said member whereby said plate acts as a centering and guiding member for the oscillating plate 13 which has surrounding relation therewith. Plate 13 is thus positioned so as to have freedom for moving in a to and fro direc-- tion, which movement is imparted thereto by the driving disc 65 through the instrumentality of the slider block 68 which operates within the elongated slot 82 formed in arm 83 integral with said oscillating plate. As the driving disc 65 rotates crank pin 61 will cause the slider block 68 to reciprocate within the elongated slot 82 and this reciprocating movement will rock arm 83, causing the plate 13 to oscillate. It will be clearly understood that the degree of oscillation of plate l3 can be controlled by the eccentricity of the crank pin 61.

For purposes of the present invention oscillating plate 73 has to and fro movement sufficient to impart indexing rotation to plate I4, Figures 1, 3 and 4, said plate having a. plurality of square teeth 85,88 and 81 formed in the periphery thereof. Said indexing plate 84 rests on top of the circular center plate 8 I, Figure 1, but oscillating plate l3 has working clearance since center plate 8i has greater thickness than plate l3. Indexing movement is given to plate 84 by the pawl 88, pivotally secured at 89 to arm 83 of the oscillating plate. As best shown in Figure 9, pawl 88 is pivotally carried by arm 83 of the oscillating plate and said pawl is yieldingl. forced inwardly by the spring detent 90 also carried by said arm 83.

Referring to Figure 3, it will be observed that pawl 88 is in contact with tooth 85 comprising one of the teeth formed in the periphery of plate 84. The oscillating plate has just been rotated in a counter-clockwise direction, and since pawl 80 was positioned back of tooth 85 similar rotation in a counter-clockwise direction was imparted to indexing plate 84. The oscillating plate, however, has continuous to and fro movement, that is, movement in a clockwise direction, and then in a counter-clockwise direction. Accordingly, return movement in a clockwise direction immediately takes place with respect to plate I3 and pawl 88 so that said pawl is caused to ride over tooth 86 and to be located back of said tooth, when the oscillating plate has reached the limit of its movement in a clockwise direction, as shown in Figure 4. It will be understood that during this movement of the oscillating plate in a clockwise direction that said indexing plate remained stationary since said plate is held by holding pawls to be presently described. The return counter-clockwise movement of the oscillating plate will result in pawl 88 engaging tooth 86 to impart another indexing rotation to plate 80 and operation of the parts will take place as described as long as rotation of the driving disc 85 continues.

Referring to Figure 1, the indexing plate 84 is suitably secured by screw St to a central hub member 92 which is positioned by portion 80 of the stud shaft I8. Thework holding plate .93 is secured by screws 94 to the top surface of said central hub member 82 and therefore it will be understood that indexing rotation of plate 84 will be transmitted to the work holding plate so that said plate will have rotation a step at a time in a counter-clockwise direction, Figure 3, to successively locate the work pieces supported by the work holding plate under the punch of the press. The periphery of the work holding plate 03 is supported by the ring 95 having an annular groove 38 therein and a depending flange 91, which flange in turn supports the ring on the flattened rib 98 provided by the member 21. Work holding stations including recessed discs I00 are provided by said plate 93 and each of said stations retains a work piece IOI within its recess. Spaced openings are formed in the work holding plate for receiving the reduced lower end of the discs I00 and accordingly the discs are fixedly secured to the plate, the same being located in spaced relation adiacentthe outer edge thereof. The discs are vertically aligned with the groove 86 in the ring 95 and an ejector I82 carried by each disc depends therefrom into the groove. The bottom of the groove may be provided with a wear plate of hardened metal to resist the wear due to the sliding contact of the electors therewith. The portion of the ring 85 extending under the punch of the press is reinforced by means of a heavier section I83 which receives an anvil I 08 having the groove 08 formed therein as a continuation of said groove in ring 95. The riveting of each work piece takes place when the disc retaining said piece is located under the punch 43 of the press, and to resist the force of this riveting operation it is necessary to reinforce the ring by the heavier section I03 and to provide the anvil I06. The brake plate I01 is locked on shaft I8 and is backed by the part I08 to form a brake by the application of pressure upon rubber discs contacting the faces of plate I0I, thus preventing free rotation of the work holding plate 93.

The mechanism for holding the indexing plate 84 and thus the work holding plate 93 in rotated position is shown in Figure 4. The same includes two holding pawls I08 and N0, the former preventing rotation of the indexing plate in a clock wise direction and pawl IIO preventing rotation of the plate in a counter-clockwise direction. Pawl I08 is supported by the pad I I I, being pivotally secured thereto at H2. The spring detent I I3 yieldingly maintains said pawl in an operative position in contact with the teeth on the indexing plate. A bridge I I4 extends rearwardly from said pawl and provides a contact point I I5 adapted to actuate a micro-switch IIS. When the pawl I08 is in engagement with the indexing plate the micro-switch is operative and the contacts thereof are closed.

Pawl I III for preventing counter-clockwise rotation of the indexing plate is pivotally supported at I I1 and said pawl is yieldingly forced inwardly toward the plate by the spring detent II8. Said pawl is also provided with a bridge I20 and a contact point I2I adapted to engage the micro switch I22 and close the contacts of said switch. As shown in Figure 4 the pawl I I 0 has been rendered inoperative by cam roller I23 which is in engagement with the finger I24 of said pawl. Cam roller I23 is carried by the arm I25 of the oscillating plate 73 and clockwise rotation of said plate is designed to bring the cam roller I23 into contact with finger I24 to cam the pawl IIO into an inoperative position. In this position, the contacts of the micro-switch I22 are permitted to open and the pawl has been released from engagement with the teeth of the indexing plate 84. It will be clearly understood that it is first necessary to release pawl IIO from engagement with the plate 84 since indexing rotation of the plate is in a counter-clockwise direction. This is the function of cam roller I23 and said roller will hold the pawl IIO out of contact with the indexing plate until indexing rotation thereof has been initiated by the pawl 88. Just as soon as the tooth 81 has been located under the pawl, the pawl is automatically released since the cam roller I23 will move out of contact with finger I24. The pawl I I0, however, can not drop into a tooth space until full indexing rotation of plate 84 has taken place.

The operation of pawl I08 is automatic and this pawl will allow indexing rotation of plate 84 but is operative at all times, except'when on top of a tooth, to prevent reverse movement of the plate. The micro-switches associated with pawls I08 and I I0 normally have open contacts. The said contacts are therefore closed when the pawls drop into place within a tooth space, which can be described as the operative position of said pawls, since in this position the indexing plate is held against rotation in a counter-clockwise as well as a clockwise direction. The third micro-switch i2 is associated with plunger "I0 which is actuated by cam 66 on the driving disc 85. Cam 85 is located on the driving disc so as to actuateplunger it immediately following an ind operation. such a position of the parts is shown in e 3, wherein it will be observed that pawl Hi8 pawl lit are operative and the contacts of their micro-switches are therefore closed. Actuation of plunger it will also result in closing the contacts of micro-switch l2 and accordingly the circuit electrically connecting with the solenoid IE6 is closed, as will be clearly understood by reference to the wiring diagra'm of Figure 12. When the solenoid is energized the clutch of the punch press is tripped and a punc operation takes place. The stations on the work holding plate have been located so that the indexing rotation Just referred to will result in successively locating the discs mo under the punch d3 of the press. When all three switches E2, M5 and i22 have been closed the press is tripped by the action of the solenoid and the punch 43 descends into contact with the rivet of a work piece, thereby riveting the same and securing the various parts of the work piece in assembled relation.

Upon the succeeding indexing rotation of the work plate the riveted work piece will be moved out of alignment with the punch and another work piece will be moved into the position previously occupied by the same. The riveting position is shown in Figure 6 and the work pieces following a riveting operation are shown in Figure 7. It is now necessary to eject the riveted work piece from the disc Hill in order that additional parts may be located therein in proper relation for assembling the parts. For ejecting the riveted work pieces the ejector m2 is camme'd upwardly by thecam surface I21 placed in the groove 96, Figure -7. This upward movement of the ejector elevates the work piece to remove the same from the retaining recess in its disc and the work piece thus released can be removed manually, ora blast of air can be directed against the same to automatically deposit the work piece into a container provided therefor.

In the present machine the work stations Hill on the work holding plate equal the number of teeth in the indexing plate 34!. This construction is characteristic of the invention and it will be understood that the indexing rotation is equal to the distance between work stations so that at the end of each indexing operation a work station is located under the punch and properly aligned therewith, The speed at which these stations may be rotated can be varied independently of the driving speed of the press, although'the indexing operation controls the riveting operation through the three switches, namely, 72, H6 and H22. All three switches are closed to energize the solenoid E26 when three conditions have been fulfilled. Two of these conditions require that the pawls Hi3 and till be located within a tooth space in the indexing plate 8% so that the plate is definitely held against movement. Switch it I is closed simultaneously with or slightly after the completion of an indexing movement and at this point in the operation of the apparatus the circult to the solenoid is completely closed, energizing the same to attract the armature H28 which causes the same to move in a downward direction. Link I29 connects said armature with the lever [30 pivotally secured at i3! to the standard-3d of the press. The connection I32 joins lever tit to the vertical rod I33 so that movement of the lever is imparted to the rod. The tension spring lid is provided for yieldingly maintaining lever lit and armature H28 in an elevated or inoper= and aerated v I atlve position, which likewise main la:

lever ltt in a similar position, since rod 833 pivotally connects therewith at H36. Lever 888 is secured to standard 30 of the press at I31 and the free outer. end of the same connects with the upright clutch tripping rod 138, having releasable connection with the tripping member I40 for the clutch diagrammatically illustrated by numeral 41. Said clutch is of the conventional overrunning type wherein the clutch parts are housed within the hub of the fly-wheel 35. The said parts are normally maintained inoperative since the cam portion MI is held in contact with the tripping member I40. When the parts are in this position the fly-wheel 35 has rotation on shaft 33 but said shaft is held stationary, which stationary position has been predetermined so as to maintain the punch in elevated position.

The apparatus of the invention requires that one or more operators manually assemble the various parts of the work pieces as the respective work stations move with the rotation of the work holding plate. For example, the first operator, having a location adjacent the point where the work pieces are ejected, will begin the assembling operation by locating within each disc tilt the body portion of the work piece and the insulating washer to be associated therewith. The next operator who may be positioned substantially in front of the machine will then locate on the partly assembled work pieces one of the several metal discs and possibly another insulating washer. The last operator will then place on the work piece one or more metal discs and the last insulating washer. The work pieces are then ready to pass under the punch of the press, whereupon the body portion is riveted to securely unite the various metal discs and washers assembled thereon. The clutch ti is tripped each timethe tripping member M0 is moved out of contact with the cam portion ldi. This releases the clutch and permits a riveting operation to take place. The clutch tripping rod lit has releasable action with tripping member Mt, which permits member M0 to'return immediately to its operative position to engage the cam portion Ml following one complete revolution thereof.

Referring to the wiring diagram of Figure 12, the press motor 37 ,is directly connected to the power lines L1, L2 and La through conductors M2.

The source of power is indicated as three-phase alternating current and a suitable make and break type of electric switch M3 is located in the circuit to the motor so that the motor may be started and stopped by actuation of said switch. The constantly running electric motor 52 for the dial feed is likewise connected through conductors led with the power lines L1, L2 and La. Numeral M5 indicates the make and break type of electric switch located in the circuit to said feed motor. Even after the switch I45 has been closed the feed motor will not start until the magnetic starter containing the magnetic coil X and indicated in its entirety by numeral 5 has been energized. Conductors It? and fled connect a starting switch and an emergency stopping switch to said magnetic starter. Conductor Ml connects with the stopping switch ltd and starting switch i5l. Switch I5! is normally open,

whereas, the emergency stopping switch is normally closed. When switch l5l is pressed the circuit is closed to the magnetic starter, thereby energizing the'same, and after switch It! returns to its open position the magnetic starter remains energized by reason of the by-pass conductor 852. On the other side of the magnetic starter conductor I53 connects power line Ll with the magnetic coil I54 of a relay having a contactor I 55. The conductor I56 connecting with power line LE2 divides so as to electrically connect with the solenoid I26 through conductor I51 and with the micro-switches through conductor I58. The wiring diagram shows the micro-switches I2, I I6 and I22 as electrically connected and as normally open switches. The circuit from said switches is completed by conductor I60 leading to the magnetic coil I51 of the relay. The circuit from the solenoid I26 is completed by conductor IBI which also connects with the relay. It will be understood from the wiring diagram that when all three micro-switches are closed that the relay is energized so that the same will attract its contactor I55, thereby closing the circuit to the solenoid I26 and energizing said solenoid. This results in actuation of the mechanism to trip the clutch on the press and a riveting operation thereupon takes place to rivet a work piece in a manner as has been described.

Referring to Figure 5, it can be seen. that cam 56 closes circuit in conductor I60 only for an instant because the cam 66 strikes plunger III in passing by the same. The duration of contact can be varied by varying the length of cam 65. As soon as cam 66 passes by plunger the circult in conductor IE0 is broken and solenoid I26 is deenergized. Then spring I34 of Figure 8 returns all tripping linkage back to stopping position. This making and breaking of contact by switch I2 has a shorter time interval than is necessary for the press to complete one cycle. 4

The invention is not to be limited to or by details of construction of the particular embodiment thereof illustrated by the drawings, as various other forms of the device will of course be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

What is claimed is:

1. In a dial feed for a press having a reciprocating punch and driving means therefor, a workholding plate supported for rotation of its periphery under said reciprocating punch, an indexing plate for securement to said workholding plate, said indexing plate having a plurality of teeth on the periphery thereof, an. oscillating member associated with said indexing plate, means for imparting to and fro movement to said member, a pawl carried by the member and having coaction with the teeth on the indexing plate for imparting movement to the plate during movement of the oscillating member in one direction only, other pawls also having coaction with said teeth for holding the indexing plate to prevent rotation thereof between indexing movements, and a cam roller on said oscillating direction only, mean holding said indexing plate preventing rotation thereof between said indexing movements including a pawl adapted to coact with the teeth on the plate for preventing clockwise rotation and a second pawl also adapted to coact with the teeth on the plate for preventing counterclockwise rotation. and a cam roller on said oscillating member for automatically releasing said second pawl during retrograde movement of the member.

3. In a dial feed for a press having a reciprocating punch and driving means therefor, a workholding plate supported for rotation of its periphery under said reciprocating punch, means for imparting indexing movements to said workholding plate, members for holding said plate preventing rotation thereof between indexing operations, and means actuated by said members for opening and closing an electric circuit.

4. In a press, a reciprocating punch and driving means therefor, a workholding plate supported for rotation of its periphery under said reciprocating punch, means for imparting indexing movements to said workholding plate, members for holding said plate preventing rotation thereof between indexing operations, switch means actuated by said members for opening and closing an electric circuit to thereby control the having coaction with the teeth on the indexing plate for imparting movement to the plate during movement of the oscillating member in one punching operations of the press, said switch means having a circuit closing position to render the punch operative when said members are located to hold the workholding plate against rotation.

5. In a press, a reciprocating punch and driving meanstherefor, a workholding plate supported for rotation of its periphery "nder saidreciprocating punch, means for intermittently rotating said workholding plate including an indexing plate secured thereto and having teeth on its periphery, an oscillating member in associated relation with the indexing plate, an indexing pawl on the member for coaction with the teeth on said plate for imparting movement to the plate during movement of the oscillating member in one direction only, other pawls having locking relation with the teeth, on said indexing plate for holding the same to prevent rotation thereof between indexing operations, an electric switch in associated relation with each pawl and adapted to be actuated thereby, each said switch being located in circuit closing position when its respective pawl has holding relation with the indexing plate, a normally open switch adapted to be actuated to circuit closing position following each indexing operation, and means electrically connected in circuit with said switches and controlled thereby for determining the operations of said reciprocating punch.

6. In a press, a reciprocating punch and drivmg means therefor, a workholding plate supported for rotation of its periphery under said reciprocating punch, means for intermittently rotating said workholding plate including an indexing plate secured thereto and having teeth on its periphery, a member for advancing said indexing plate, a rotating driving disc for imparting to and fro movement to said member,

means having engagement with the teeth on said indexing plate for holding the same to prevent rotation thereof between indexing operations, an electric switch adapted to be actuated by said means into circuit closing position when said means has holding relation with the indexing plate, a normally open switch adapted to be actuated into circuit closing position during each revolution of said driving disc, and means electrically connected in circuit with said switches and controlled thereby for determining the operations of said reciprocating punch.

7. A punch press having, in combination, motor means for operating said press. an electric' solenoid controlling the operation of said press to effect reciprocation of the punch thereof; a workholding plate having a plurality of work retaining stations thereon, means for intermittently rotating said plate to successively locate said stations under the punch of the press including indexing means for said plate, members having locking engagegment with said indexing means to prevent rotation of the workholding plate between indexing operations, an electric switch adapted to be actuated by each member into circuit closing position when the member has holding relation with the indexing means, and means electrically connecting said switches in circuit with said solenoid whereby the operations of said reciprocating punch are controlled.

RUDOLPH A. SKRIBA. EDGAR R. MILLER. FREDERICK M. LIT'I'ELL. 

